The present invention relates generally to communication systems and in articular, to a method and apparatus for relaying information in ad-hoc networks.
A communication system may use ad-hoc networking to improve its performance. As described in the international application published under the Patent Cooperation Treaty, publication number WO 00/54539, ROUTING IN A MULTI-STATION NETWORK, which is incorporated by reference herein, increased coverage reliability and increased throughput are some of the benefits of using ad-hoc networking. In cellular communication systems utilizing ad-hoc networking, cellular handsets are equipped to operate in both the cellular and ad-hoc networks. Users access the cellular infrastructure through the ad-hoc network whenever they cannot access the cellular network directly, or when they find it more advantageous to do so. Using an ad-hoc air interface, such users transmit to another user, which forwards (relays) the transmission to the infrastructure through the cellular air interface. Such a system is shown in FIG. 1.
As shown, remote (or mobile) unit 102 existing within area 101 is unable to communicate directly with infrastructure equipment 106. By utilizing ad-hoc networking, remote unit 102 communicates with remote unit 104 (via ad-hoc air interface 103). Remote unit 104 then relays the communication to infrastructure 106 via air interface 105.
Because a mobile unit that is acting as a relay to other mobiles is consuming its battery reserve, there is a general concern that users would be unwilling to act as a relay if battery consumption is too great. This would hinder the development of ad-hoc networking in cellular systems. Therefore, a need exists for a method and apparatus for relaying communications within an ad-hoc network that reduces the amount of battery consumption for those remote units relaying communications.